Steam Generating Plant
The steam generating plant consists of a boiler and other auxiliary equipments for the utilization of flue gases.
1. Boiler: The heat developed due to the combustion of coal is utilized in the boiler for converting the water into steam at high temperature and pressure.
The flue gases from the boiler will flow through super heater, economiser, Air pre-heater and finally exhausted to the atmosphere through the chimney.
2. Super Heater: The steam produced from the boiler is wet and if this steam passes through the steam turbine causes the turbines may get damaged. In order to avoid this condition the steam produced from boiler is further heated at super heater. It is as shown in fig
The main function of super heater is to increase the temperature of the steam about the boiling the heat from the flue gases.
The super heater provides the following benefits namely.
i) increases
the overall efficiency
ii) Reduces
the condensation losses at the last stages of the turbine
iii) Reduces the erosion of steam turbine blades due to the absence of moisture.
3. Economiser: An economiser is essentially a feed water heater. The feed water is fed to the economiser before supplying to the boiler. The main function of economiser is that it will increases the temperature of feed water by utilizing the heat from the hot flue gases.
4. Air preheater : It is placed in between boiler and economiser. It increases the temperature of the air supplied for coal burning by deriving heat from flue gases. Air is drawn from the atmosphere by a forced draught fan and is passed through air pre-heater before supplying to the boiler furnace. The air preheater extracts heat from flue gases and increases the temperature of air used for coal combustion. The benefits’ of preheating the air are: increased thermal efficiency and increased steam capacity per square metre of boiler surface. fig
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